WPC Met Watch |
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Mesoscale Precipitation Discussion: #0276 (2019) |
(Issued at 511 AM EDT Thu May 23 2019
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MPD Selection |
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Mesoscale Precipitation Discussion 0276
NWS Weather Prediction Center College Park MD
511 AM EDT Thu May 23 2019
Areas affected...Missouri...Central Illinois
Concerning...Heavy rainfall...Flash flooding possible
Valid 230910Z - 231410Z
Summary...Early morning convection continues across the
mid-Mississippi River Valley and with hourly rates approaching
1.5-2" at times over saturated soils, flash flooding is possible.
Discussion...Water vapor imagery showed anomalous shortwave energy
over northern Minnesota early this morning, moving eastward across
the northern Great Lakes. Its surface boundary is across portions
of Illinois and Missouri, and has become stalled and
quasi-stationary given its removal from the better forcing to the
north. As such, lines of convection, including a MCV over northern
Indiana, have progressed since last evening from northeast
Oklahoma into southern Michigan. The southwest half of this line
has become more west-east oriented in the last 1-2 hours, thanks
to forcing aloft lifting northeast.
The environment as of 09z still shows a bubble of surface-based
instability along/south of the lines of convection within a belt
of 40-50 kt effective shear and PWs of 1.7-1.8". Radar returns
from KILX, KVWX, and KLSX show hourly rates as high as 2" embedded
within the deeper convection.
Through 15z, convection across southwest Missouri will continue to
lift east/northeast while storms across central Illinois remain
oriented west/east. This could set up a training scenario given
the mean flow is out of the southwest. For the next few hours, 850
mb flow is expected to remain 40-50 kts, helping to sustain the
convection. Hi-res models indicate between 1-3" with locally
higher amounts 3-4" possible through 15z, with two areas of
maximum QPF (southwest MO and central IL).
Finally, the storms are tracking over saturated ares with reduced
flash flood guidance. 1-hr values are as low as 1.5-1.0 across
central Illinois while most of southwest MO, southeast KS, and
northeast OK having seen several inches of rain in the last 12-24
hours. NWM streamflows are running very high, so any additional
rainfall will likely go straight to runoff.
As a result, instances of flash flooding will continue through the
mid-morning hours from portions of southeast KS, southwest MO
through central IL.
Taylor
ATTN...WFO...ICT...ILX...IND...LSX...PAH...SGF...TSA...
ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...OHRFC...
LAT...LON 39908726 39878579 38818676 37369006 36929150
36509505 37439553 38489252 39318941
Last Updated: 511 AM EDT Thu May 23 2019
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